IBM unveils smallest light-emitting carbon nanotube

IBM has been developing a variety of light-emitting carbon nanotubes for years, having demonstrated the first example in 2003.

At IBM Corp.’s Thomas J. Watson Research Center recently, the company has shown off the smallest example yet. Researchers placed a light-emitting nanotube (LEN) inside an optical waveguide for the purposes of directional surface emission, wavelength control and better efficiency.

After fabricating a single nanotube-based field-effect transistor, engineers attached a pair of metallic mirrors, one above (gold) and below (silver) the nanotube. Light was emitted from the nanotube into the cavity, which was filled with transparent dielectric. This construction confined wavelengths to the desired 1.5-μm communications frequency, suggesting the appearance of future silicon photonics devices.

Scientists estimate the efficiency gain over the usual broad wavelength LEN at 400%.

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SOURCES: EE Times; IBM